Although this invention is directed principally to the measurement of direction and/or rate of groundwater flow in order to determine the environmental effect, for example, of septic leachate upon natural water systems, the basic principles of this invention are applicable to a wide range of problems in which the velocity and/or direction of fluid flow is in question.
At present, many systems and techniques have been developed to provide information about the direction and/or rate of a fluid flow, including systems which rely on steady state heating a tube through which a liquid flows and measuring temperatures of the moving liquid at upstream and downstream locations relative to the heat source, to obtain a hyperbolic measurement of flow rate. However, none has to my knowledge been developed which involves measurement of the distortion of a thermal field established by locally heating a permeable mass through which the fluid flows, to obtain a linear measurement of fluid flow rate.